The present invention generally relates to a method and an apparatus for growing thin film, and more particularly for growing a composite metal sulphide photocatalyst thin film.
With development of highly efficient photocatalyst materials as reported in scientific researches, their uses and applications have been widely extended to different fields. For example, in a hydrolysis reaction catalyzed by a photocatalyst, a water molecule is broken down to produce hydrogen, water and carbon dioxide for generating fuels such as methanol, methane and so on. The photocatalyst has also been used conventionally for creating a better amenity environment. For example, transparent titanium oxide (TiO2) film photocatalyst has been utilized under visible light or ultraviolet (UV) irradiation to decompose odors, bacteria and stains during the process of sterilization, oxidative decomposition, and deodorization.
Typically, most of the photocatalysts have been manufactured with material in the form of powders. Yet, it is more favorable, in terms of industrial applicability to manufacture a photocatalyst thin film which facilitates the design of industrial photoreactors. Japanese Patent JP2002-20108 has disclosed a method and apparatus for forming semiconductor thin film in aqueous solution. The photocatalyst thin film was formed by photochemical deposition (PCD) on a substrate that was irradiated with a light source. Japanese Patent JP2003-181297 has disclosed formation of a thin film-like photocatalyst by dipping a base material into the solution containing Zn and depositing ZnS, ZnO or the like on the surface of the base material by a chemical bath deposition (CBD) method.
However, none of the studies has been directed to manufacturing a composite metal sulphides photocatalyst thin film which is grown on a large scale basis.